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Migration Woes

QCC Correlations

Science Standards 3.12, 4.23, 4.25

Objectives

The Students will be able to:

  • Describe the reproductive cycle of the gopher frog.
  • Describe the impacts of habitat loss and degradation on gopher frog populations.
Materials Needed:
  • Large playing field or gymnasium
  • Cones or other objects to mark boundaries of field
  • Two paper plates, carpet samples, or hoola hoops for every three students
Procedure:

Background:

The gopher frog depends on two types of habitats. It spends most of its adult life away from water in dry, sandy uplands such as Longleaf pine forests. During the late fall and early winter, the frogs migrate to their breeding grounds. The frogs depend on ephemeral ponds, which are temporary and only full of water right after heavy rains. The frogs lay masses of eggs at the base of vegetation and the larval period takes about 4 months. When metamorphosis is complete, the new adults migrate to the dry uplands.

The gopher frog gets its name from its relationship with the gopher tortoise. The gopher frog lives in gopher tortoise burrows. The gopher frog is an animal of conservation concern because it is losing both of its habitats (breeding ponds and uplands) to development and farming. Gopher frogs, like all amphibians are also sensitive to pollution.

Procedure:

1) Select a large playing area about 70ft in length. Use the cones to mark the boundaries. Place the paper plates in two patches on the ends of the playing field.


70 ft

2) Designate one of the areas as the upland habitat and the other the breeding pond.

3) Explain to the students that they are gopher frogs and will migrate between these two areas. At the end of the journey, the students will have to have one foot on a paper plate in order to be allowed to continue. If a student cannot get his/her foot on a plate, that means she/he has not found suitable habitat and is now "dead". The "dead" frogs move to the sideline to watch. Tell students that in this activity only three frogs can occupy a paper plate at any one time.

4) Explain to students that many factors will limit the survival of the gopher frogs including enough habitat, availability of ponds, and clean water.

5) Begin the activity with all the students at the breeding pond. Announce the start of the migration to the uplands. Have the students migrate in slow motion until they become familiar with the process. On the first try, all of the frogs will successfully migrate to the uplands. Before the students migrate back to their breeding ponds, remove one plate from that region. Explain that a pond area has been cleared for a pine plantation (tree farm). Announce the start of the second migration and send the frogs to the breeding pond. Tell the "dead frogs" that they can come back as surviving tadpoles when favorable conditions prevail and there is habitat available in the breeding pond.

6) Note - the series of migration cycles can be graphed.

7) Before the next migration, remove four more plates in the upland habitat. Tell the students that this is the result of a new housing development. Announce the third migration.

8) Repeat this process for eight or ten migration cycles to illustrate changes in habitat conditions with resulting effects on the frogs. Remember to provide "dead frogs" with chances for re-entry by returning some paper plates periodically, signifying an improvement in habitat.

 

Factors limiting survival of gopher frogs:
Drought, pollution and contamination of water, conversion of ephemeral pond areas to pine plantations, decrease in gopher tortoise populations, habitat loss to development, conversion of ephemeral ponds to permanent ponds with fish (fish eat the frog eggs), fire suppression

Factors favoring survival of gopher frogs:
Preservation of wetlands, high rainfall, restoration of habitat, reducing polluted runoff, increase in tortoise populations

9) After the activity, discuss with students the causes of the frog's population decline from year to year. Ask them to try to identify the major factors contributing to habitat loss. Have them distinguish between short term and long-term effects. Have them distinguish between natural and man-made causes. Compare similarities and differences between these limiting factors.

10) Ask students to identify the factors that they believe pose the most significant long-term threats for the survival of the gopher frog?

11) What types of things can be done to protect and restore habitat for the frogs? What can the students do to help. Discuss potential trade-offs related to any recommendations.

Source: Adapted from Animal Tracks: Habitat Activity pack, National Wildlife Federation